Use the reaction to answer the question.

Question

heat + PCl^5(g) ⟷ PCl^3(g) + Cl^2(g)

What changes can you make to increase the amount of reactant at equilibrium in this reaction?

1. decreasing the temperature
2. removing the product
3. adding more reactant
4. increasing the pressure

Answer 1

To increase the amount of reactant at equilibrium in this reaction, you can make the following changes:

1. Increasing the temperature: According to Le Chatelier's principle, increasing the temperature will favor the endothermic direction of the reaction. In this case, increasing the temperature will favor the reaction going to the right, resulting in more reactant at equilibrium.

2. Removing the product: By removing the product (Cl2), you are essentially decreasing its concentration, which will shift the equilibrium towards the reactant side in order to restore the equilibrium. This will result in an increase in the amount of reactant.

3. Adding more reactant: By adding more PCl5, you are increasing its concentration, which will shift the equilibrium towards the product side in order to restore the equilibrium. This will result in an increase in the amount of reactant being converted to product.

4. Increasing the pressure: Increasing the pressure of the system will compress the gas molecules, resulting in an increase in the concentration. According to Le Chatelier's principle, increasing the pressure will favor the direction with fewer moles of gas. In this case, the reaction will favor the product side and more reactant will be converted to product.